beginning i2c

[rsbs2] / bmc / i2c.c

#include <util/twi.h>
#include <avr/interrupt.h>
#include <stdio.h>
#include "i2c.h"

#define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);  
#define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
#define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);  

void i2c_init()
{
	TWAR = BMC_ADDR;
	TWCR &= ~(1<<TWSTA)|(1<<TWSTO);
	TWCR|= (1<<TWEA) | (1<<TWEN)|(1<<TWIE); 
}

ISR (TWI_vect)
{
	printf("Interrupt, Status: %02x!\n", TW_STATUS);

	switch (TW_STATUS) {
		default:
			TWCR_RESET;
			break;
	}
}